I have no burden to provide anything but I did anyway out of courtesy

You provided a source and then claimed it says something it doesn't. That's not courtesy, that's spreading falsehoods. When people called you out on it, you doubled down. That goes from saying something false, which we all do occasionally even when we don't intend to, to lying. If you don't want to back up your claims, you can say that. But that's not what you did, and that's why people have a problem with this behaviour.

So there is, according to your own words, absolutely no credible evidence that Ubuntu is popular on desktops at all.

This is what's known as moving the goalposts. Stating that we don't have the data to provide an answer to everyone's satisfaction is not the same as saying that there's not credible evidence of Ubuntu's popularity.

So everybody here claiming how popular Ubuntu is, is making claims without backing them up.

Well let's examine the very comment to which you replied:

[Ubuntu is] one of the top most used distros probably

Not only did @embed_me@programming.dev say something that general context of the industry tends to say is likely, they also caveated their statement with a "probably."

Not only that, but the very screenshot you keep sharing actually provides evidence for that. Ubuntu is in the top 5 distros listed.

Funny how your fervor isn’t with them and their “burden to provide a good backing for said claim”.

Because their statements match my current informed understanding of the state of things (so I don't feel the need to ask them where they're getting their info) and, more importantly, they're not making toxic replies and personal attacks. They're not, in what I've read, telling you to shut up. Rather, most of the replies I've read to your comments have been unfailingly polite, which is more than I can say of your own comments.

Seems you are not that objective about that matter.

I'm not objective in the matter, and neither are you. However, I'm also not claiming that Steam OS isn't popular. It's undoubtedly popular, and on a personal note I'm a fan of it. What I am claiming is that the data you're using doesn't back up your statement.

Fact is, Steam is widely used by “regular” people (which this sub-thread is about) and therefore the best statistic there is about distribution usage outside the “techie sphere”.

There's the problematic leap. Steam is widely used, yes. And the Steam survey is a great tool for helping game developers decide where to target their games. But that doesn't make it a good statistic about general distro usage, for numerous reasons, including (but not limited to):

1. It is likely to overrepresent the Steam Deck for the same reason a survey of Snap users would overrepresent Ubuntu.
2. Steam users are not necessarily representative of all Linux users.
3. Where someone uses Steam OS is not necessarily representative of their everyday usage.
4. Given that the Steam Deck is primarily an appliance, its use of Linux no more makes someone who's playing on a Steam Deck a Linux user than someone with a TV running Tizen is a Linux user.